Proteins surface free energy

Only a few studies have been published with regard to the influence of fluoride treatment on pellicle formation and composition. Contrary results have been reported concerning in vitro salivary protein adsorption on fluoride-treated enamel (table 4). Treatment of pellicle-covered as well as bare enamel surfaces with amine fluoride causes a decrease in surface free energy [184, 185], However, fluoridation of the enamel surface with sodium fluoride does not significantly influence the amino acid composition of the pellicle layer adsorbed in vivo [186], In contrast, stannous fluoride treatment of enamel... 

KitaY, Arakawa T, Lin TY, and Timasheff SN. Contribution of the Surface Free Energy Perturbation to Protein-solvent Interactions. Biochemistry 1994 33 15178-15189. 

Surface Free Energy Changes in Protein Aggregation... 

The surface free energy, Fs, of the protein can be calculated in terms of two parameters A, the area of the molecule in contact with the solution, and a, the surface charge density (a = charge per A) ... 

Conformational changes are frequently invoked to describe biochemical mechanisms qualitatively. With the surface free energy model, it is possible to evaluate the energetic consequences of conformational changes in proteins. We have done this for the ligand-binding reactions of hemoglobin (8). 

Many interesting correlations have been established between the critical surface tension of materials (or other approximations of surface free energy) and protein adsorption, cell adhesion, and thrombus formation (41-48). Unfortunately, very few studies in which a biological response has been related to a specific surface chemistry exist. One study in which such a relationship was established, demonstrated the power of the contact angle method in analyzing surface structure related to blood compatibility (40). The blood compatibility of Stellite alloy heart valves was not due to the alloy itself, but to the closely packed methyl group structure associated with a tallow polishing compound used to finish the valve. Very recently, the power... 

The postulate of Vroman addresses only one variable, namely concentration, that may be expected to influence a protein s adsorption competitiveness. From known adsorption principles we may reasonably assume that protein affinity for the surface (free energy of adsorption), protein-protein interactions in the layer, and kinetic factors such as activation energy of adsorption will also influence competitive adsorption. The idea of a sequenced based at least partly on concentration seems reasonable, since initially difTusion would ensure relatively high concentrations of the abundant proteins, and only later would the true relative affinities of the proteins for the surface be expressed. This idea raises tantalizing questions such as whether all surfaces end up with the same protein layer or whether the sequence stops at different points on different surfaces. 

Table 7 Surface Free Energy Components (in mJ/m ) for Polymers, Fibres, Metal Oxides, Glass, Microorganisms and Proteins... 

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